I see Dell has some diags give it a shot.
https://www.dell.com/support/home/us/en/04/product-support/product/inspiron-15-3542-laptop/diagnose
I recently upgraded my router to speeds of 100 MBPS. When I checked through "Speedtest" ,while connected to WiFi it only marked up to 40 or so. Then I connected it to the Ethernet, same thing.
I called the provider, the technician did the same and his computer went up to 110 MBPS!!
I've googled this and found that if I uninstall an app called "Smartbite" it would solved all my problems but it didn't. It improved a bit but still.
I have re-installed drivers, ran Dell Assistant but nothing.
It isn't a hardware problem since WiFi and Ethernet are separate systems and both are capable of handling much higher speeds. I suspect it is a Windows 10 problem but I am at a loss.
HELP!!!

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